From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A999EECE58C for ; Wed, 9 Oct 2019 16:44:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82C7D206BB for ; Wed, 9 Oct 2019 16:44:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731818AbfJIQof (ORCPT ); Wed, 9 Oct 2019 12:44:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:56018 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729644AbfJIQof (ORCPT ); Wed, 9 Oct 2019 12:44:35 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 57B1DAC7D; Wed, 9 Oct 2019 16:44:33 +0000 (UTC) Received: by unicorn.suse.cz (Postfix, from userid 1000) id AD5D1E3785; Wed, 9 Oct 2019 18:44:32 +0200 (CEST) From: Michal Kubecek Subject: [PATCH net-next] genetlink: do not parse attributes for families with zero maxattr To: "David S. Miller" Cc: Jiri Pirko , Johannes Berg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Message-Id: <20191009164432.AD5D1E3785@unicorn.suse.cz> Date: Wed, 9 Oct 2019 18:44:32 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function") moved attribute buffer allocation and attribute parsing from genl_family_rcv_msg_doit() into a separate function genl_family_rcv_msg_attrs_parse() which, unlike the previous code, calls __nlmsg_parse() even if family->maxattr is 0 (i.e. the family does its own parsing). The parser error is ignored and does not propagate out of genl_family_rcv_msg_attrs_parse() but an error message ("Unknown attribute type") is set in extack and if further processing generates no error or warning, it stays there and is interpreted as a warning by userspace. Dumpit requests are not affected as genl_family_rcv_msg_dumpit() bypasses the call of genl_family_rcv_msg_doit() if family->maxattr is zero. Do the same also in genl_family_rcv_msg_doit(). Fixes: c10e6cf85e7d ("net: genetlink: push attrbuf allocation and parsing to a separate function") Signed-off-by: Michal Kubecek --- net/netlink/genetlink.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index ecc2bd3e73e4..c4bf8830eedf 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -639,21 +639,23 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family, const struct genl_ops *ops, int hdrlen, struct net *net) { - struct nlattr **attrbuf; + struct nlattr **attrbuf = NULL; struct genl_info info; int err; if (!ops->doit) return -EOPNOTSUPP; + if (!family->maxattr) + goto no_attrs; attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack, ops, hdrlen, GENL_DONT_VALIDATE_STRICT, - family->maxattr && family->parallel_ops); if (IS_ERR(attrbuf)) return PTR_ERR(attrbuf); +no_attrs: info.snd_seq = nlh->nlmsg_seq; info.snd_portid = NETLINK_CB(skb).portid; info.nlhdr = nlh; -- 2.23.0